Hello everyone i live in a small village in Northumberland in the UK i have had an unhealthy interest in all things crossbow since i was a lad i own an old Barnett Wildcat from the 70s and i have a homemade with a shaped leaf spring as a power source it shoots reasonably well but i still have lots to learn.Thorn'

Hey Thorn Welcome to the site Now if you like crossbows you found the home / house of crossbows Modern > Medieval. Making a Prod (bow) from an old auto leaf spring works? I made one many years ago when I was still a kid?! Be careful as this way is very dangerous. It can and will ruin your whole day. Have funfore you are with a group of great guys all willing to help. Take care now. Mike

Michael wrote:Hey Thorn Welcome to the site Now if you like crossbows you found the home / house of crossbows Modern > Medieval. Making a Prod (bow) from an old auto leaf spring works? I made one many years ago when I was still a kid?! Be careful as this way is very dangerous. It can and will ruin your whole day. Have funfore you are with a group of great guys all willing to help. Take care now. Mike

I used leaf springs for crossbow prods exclusively until I started experimenting with wooden bowmaking a few years back. The leaf spring leaves I use are new, not used. Now, I would argue that a properly heat-treated and designed steel prod is not any more dangerous than any other prod that stores the equal amounts of energy. I think the reason for the bad reputation of leaf spring prods is twofold:

They're easy to make without knowing much/anything about bowmaking and due to this they've been almost always designed badly

They store large amount of energy

Bad design combined with high energy storage is a good recipe for a disaster.

Now, there are several things to remember when making a safe and efficient steel prods:

Ensure there are no weak points (e.g. the hole in the middle, look here for ideas)

The width taper is proper, so that all parts of the bow bear equal load (look here)

The steel is heat-treated so that the prod bends before breaking (look here)

Draw length is increased slowly to see if the prod gains "set" (=bends without returning to it's original form)

The areas around the width tapering cuts are ground or filed cold, so that the softened areas are removed

That said, used leaf springs are usually rusty to the extent they have small pits all over their surface. These obviously reduce the integrity of the bow somewhat. However, unlike with wooden bows, this is not critical. It will hold together just fine.